WO2018042750A1

WO2018042750A1 - Semiactive damper

Info

Publication number: WO2018042750A1
Application number: PCT/JP2017/015735
Authority: WO
Inventors: 貴之小川
Original assignee: Ｋｙｂ株式会社
Priority date: 2016-08-30
Filing date: 2017-04-19
Publication date: 2018-03-08
Also published as: JP2018035829A; US20190126950A1; CN109642632A; JP6879695B2

Abstract

The semiactive damper (D) according to the present invention is provided with: a cylinder (1); a rod (2) inserted movably within the cylinder (1); a piston (3) which is slidably inserted in the cylinder (1) and divides the interior of the cylinder (1) into a rod side chamber (4) and a piston side chamber (5); a tank (6); an inlet passage (7) permitting only a flow of a working fluid from the tank (6) toward the piston side chamber (5); a damping passage (8) putting the rod side chamber (4) and the tank (6) in communication or putting the rod side chamber (4) and the piston side chamber (5) in communication; a variable damping valve (9) provided to the damping passage (8); and a detection unit (10) for detecting the expansion and contraction direction due to pressure in the piston side chamber (5).

Description

Semi-active damper

The present invention relates to an improvement of a semi-active damper.

Conventionally, in this type of semi-active damper, for example, a railway vehicle is used by being interposed between a vehicle body and a carriage so as to suppress left-right vibration with respect to the traveling direction of the vehicle body. Are known.

More specifically, for example, as disclosed in JP11-44288A, the semi-active damper includes a cylinder, a piston that is slidably inserted into the cylinder, and divides the cylinder into a rod side chamber and a piston side chamber, A rod inserted into the cylinder and connected to the piston and provided in the middle of the first passage communicating the actuator, the tank, the rod side chamber, and the piston side chamber, which are interposed between the vehicle body and the carriage. A first on-off valve, a second on-off valve provided in the middle of the second passage communicating the piston side chamber and the tank, a discharge passage connecting the rod side chamber to the tank, and a valve provided in the middle of the discharge passage And a variable relief valve capable of changing the pressure.

In the semi-active damper configured as above, when the first on-off valve is opened and the second on-off valve is closed, the damping force is exerted only on the contraction side, and conversely, the first on-off valve is closed and the second on-off valve is opened. It exhibits damping force only on the extension side. Therefore, the semi-active damper can function as a skyhook damper based on the carnop control.

Conventional semi-active dampers employ solenoid valves that use solenoids for the first on-off valve, the second on-off valve, and the variable relief valve, and each valve is large and expensive. Cost increases.

In addition, there is a response delay in the opening and closing of the first on-off valve and the second on-off valve. Thus, there is a problem that vibrations are excited in the vehicle body and the riding comfort in the vehicle is deteriorated.

An object of the present invention is to provide a semi-active damper capable of reducing the size and cost and improving the riding comfort in a vehicle.

The semi-active damper of the present invention includes a cylinder, a rod that is slidably inserted into the cylinder, and a piston that is slidably inserted into the cylinder and divides the cylinder into a rod side chamber and a piston side chamber. A tank, a suction passage that allows only a flow of working fluid from the tank to the piston side chamber, a damping passage that communicates the rod side chamber and the tank, or communicates the rod side chamber and the piston side chamber. And a variable damping valve provided in the damping passage, and a detector for detecting the expansion and contraction direction by the pressure in the piston side chamber.

FIG. 1 is a circuit diagram of a semi-active damper according to an embodiment. FIG. 2 is a schematic plan view of a railway vehicle equipped with a semi-active damper according to an embodiment. FIG. 3 is a control block diagram of a control unit in the semi-active damper according to the embodiment. FIG. 4 is a circuit diagram of a semi-active damper according to a modification of the embodiment. FIG. 5 is a circuit diagram of a semi-active damper according to another modification of the embodiment. It is the circuit diagram which showed the modification of the variable damping valve.

Hereinafter, the present invention will be described based on the embodiments shown in the drawings. As shown in FIG. 1, the semi-active damper D in one embodiment includes a cylinder 1, a rod 2 that is movably inserted into the cylinder 1, and a slidably inserted into the cylinder 1. The piston 3 is divided into a rod side chamber 4 and a piston side chamber 5, a tank 6, a suction passage 7, a damping passage 8, a variable damping valve 9, and a detection unit 10 that detects the expansion / contraction direction. ing.

In this example, the semi-active damper D is used as a vibration damping device for the vehicle body B of the railway vehicle, and is installed between the vehicle body B and the carriage T as shown in FIG. The horizontal and horizontal vibrations are suppressed with respect to the vehicle traveling direction B.

Hereinafter, each part of the semi-active damper D will be described in detail. The cylinder 1 has a cylindrical shape, and the right end in FIG. 1 is closed by a lid 11, and an annular rod guide 12 is attached to the left end in FIG. A rod 2 that is movably inserted into the cylinder 1 is slidably inserted into the rod guide 12. The rod 2 has one end protruding outside the cylinder 1, and the other end in the cylinder 1 is connected to a piston 3 that is slidably inserted into the cylinder 1.

When the piston 3 is slidably inserted into the cylinder 1, the inside of the cylinder 1 is divided into a rod side chamber 4 and a piston side chamber 5. Note that the outer periphery of the rod guide 12 and the cylinder 1 are sealed by a seal member (not shown), whereby the inside of the cylinder 1 is maintained in a sealed state. The rod side chamber 4 and the piston side chamber 5 defined by the piston 3 in the cylinder 1 are filled with working oil as a working fluid. The tank 6 is filled with gas in addition to hydraulic oil. In addition, it is not necessary to compress and fill the inside of the tank 6 with a gas in particular. The working fluid may use other liquids besides the working oil.

Further, a lid 11 that closes the left end of the rod 2 in FIG. 1 and the right end of the cylinder 1 is provided with a mounting portion (not shown), and a semi-active damper D is interposed between the vehicle body B and the carriage T in the railway vehicle. Can be disguised.

The damping passage 8 connects the rod side chamber 4 and the tank 6, and the damping passage 8 is provided with a variable damping valve 9. In this example, the variable damping valve 9 is a variable relief valve that can change the valve opening pressure, and can adjust the valve opening pressure in accordance with the amount of current supplied. The variable damping valve 9 opens when the pressure in the rod side chamber 4 reaches the valve opening pressure, and connects the rod side chamber 4 to the tank 6 to adjust the pressure in the rod side chamber 4 to the valve opening pressure. The flow of hydraulic oil toward the rod side chamber 4 is blocked. Therefore, in this example, the damping passage 8 is set as a one-way passage that allows only the flow of hydraulic oil from the rod side chamber 4 toward the tank 6 by the variable damping valve 9.

In this example, the variable damping valve 9 is an electromagnetic relief valve equipped with a solenoid. When the current amount is maximized, the valve opening pressure is minimized, and when no current is supplied, the valve opening pressure is maximized. The valve opening pressure is changed according to the amount of current to be applied. In addition to the relief valve that can adjust the valve opening pressure, the variable damping valve 9 has other structures such as a variable throttle valve that can adjust the opening area according to the amount of current supplied, a spool valve, a rotary valve, and the like. Valves can also be used.

Further, the semi-active damper D of the present example has a rectifying passage 13 that allows only the flow of hydraulic oil from the piston side chamber 5 to the rod side chamber 4, and a suction that allows only the flow of hydraulic oil from the tank 6 to the piston side chamber 5. A passage 7 is provided. Therefore, when the semi-active damper D of this example expands and contracts, the hydraulic oil is always pushed out from the cylinder 1 to the damping passage 8. Since the variable damping valve 9 provides resistance to the flow of hydraulic oil discharged from the cylinder 1, the semi-active damper D of this example is configured as a uniflow type damper.

More specifically, the rectifying passage 13 communicates the piston side chamber 5 and the rod side chamber 4, and a check valve 13 a is provided in the middle, allowing only the flow of hydraulic oil from the piston side chamber 5 toward the rod side chamber 4. It is set as a one-way passage. Further, the suction passage 7 communicates between the tank 6 and the piston side chamber 5, and a check valve 7 a is provided in the middle of the suction passage 7 to allow only the flow of hydraulic oil from the tank 6 toward the piston side chamber 5. Is set to In this example, the rectifying passage 13 is provided in the piston 3 and the suction passage 7 is provided in the lid 11, but may be provided elsewhere.

In the semi-active damper D configured as described above, the rod side chamber 4, the piston side chamber 5, and the tank 6 are connected in a daisy chain by the rectifying passage 13, the suction passage 7, and the damping passage 8. The rectifying passage 13, the suction passage 7, and the attenuation passage 8 are set as one-way passages.

Therefore, when the semi-active damper D is extended, the working oil is discharged from the rod side chamber 4 to be compressed to the damping passage 8, and the expanding piston side chamber 5 is replenished with the working oil from the tank 6 through the suction passage 7. Since the hydraulic oil discharged from the rod side chamber 4 moves to the tank 6 via the variable damping valve 9, the semi-active damper D sets the pressure receiving area on the rod side chamber 4 side in the piston 3 to the pressure in the rod side chamber 4. Generates a damping force of the multiplied value. On the contrary, when the semi-active damper D is contracted, the working oil moves from the compressed piston side chamber 5 to the rod side chamber 4 through the rectifying passage 13. Further, in this case, since the rod 2 enters the cylinder 1, the hydraulic oil corresponding to the volume into which the rod 2 has entered becomes excessive in the cylinder 1 and is discharged from the rod side chamber 4 to the attenuation passage 8. Since the hydraulic oil discharged from the rod side chamber 4 moves to the tank 6 via the variable damping valve 9, the pressure in the rod side chamber 4 and the piston side chamber 5 is adjusted to the valve opening pressure of the variable damping valve 9. . Since the difference between the pressure receiving area of the piston 3 that receives the pressure in the piston side chamber 5 and the pressure receiving area of the piston 3 that receives the pressure in the rod side chamber 4 is the cross-sectional area of the rod 2, the semi-active damper D has a pressure in the rod side chamber 4. A damping force having a value obtained by multiplying the cross-sectional area of the rod 2 by 1 is generated.

When the semi-active damper D expands and contracts due to an external force in this manner, the hydraulic oil is always discharged from the cylinder 1 and returned to the tank 6 through the damping passage 8, and the hydraulic oil that is not sufficient in the cylinder 1 passes through the suction passage 7. 6 is supplied into the cylinder 1. Since the variable damping valve 9 acts as a resistance against the flow of hydraulic oil and adjusts the pressure in the cylinder 1 to the valve opening pressure, the semi-active damper D functions as a passive uniflow type damper.

In the case of this semi-active damper D, the cross-sectional area of the rod 2 is halved of the cross-sectional area of the piston 3 so that the pressure receiving area on the rod side chamber 4 side of the piston 3 is half of the pressure receiving area on the piston side chamber 5 side. It is trying to become. Therefore, if the valve opening pressure of the variable damping valve 9 is the same during the extension operation and the contraction operation, the damping force generated by both expansion and contraction becomes equal, and the amount of hydraulic oil corresponding to the displacement amount of the semi-active damper D also expands and contracts. Same on both sides.

The detection unit 10 includes a pressure sensor 10a that detects the pressure in the piston-side chamber 5, and a determination unit 10b that determines the expansion / contraction direction of the semi-active damper D based on the pressure detected by the pressure sensor 10a. In the semi-active damper D of this example, when the expansion operation is performed, the hydraulic oil is supplied from the tank 6 through the suction passage 7 to the piston side chamber 5 to be expanded, so that the pressure in the piston side chamber 5 becomes substantially equal to the tank pressure. In the semi-active damper D of the present example, during the contraction operation, the hydraulic oil in the piston side chamber 5 to be compressed is supplied to the rod side chamber 4 through the rectifying passage 13, so that the pressure in the piston side chamber 5 becomes substantially equal to the rod side chamber 4. . When the semi-active damper D is contracted, the pressure in the rod side chamber 4 is adjusted to the valve opening pressure of the variable damping valve 9, so that the pressure in the piston side chamber 5 also becomes higher than the tank pressure. As described above, since the pressure state in the piston side chamber 5 is different between the expansion operation and the contraction operation of the semi-active damper D, if the pressure in the piston side chamber 5 is detected by the pressure sensor 10a, the expansion / contraction direction is detected. it can. Specifically, the tank pressure or a pressure value slightly higher than the tank pressure is preset as the threshold value, and the determination unit 10b detects the expansion / contraction direction by comparing the pressure detected by the pressure sensor 10a with the threshold value. More specifically, when the pressure detected by the pressure sensor 10a is less than the threshold value, the determination unit 10b determines that the semi-active damper D is in the extension operation, and outputs a signal indicating the extension operation to the control unit C. To do. When the pressure detected by the pressure sensor 10a is equal to or greater than the threshold value, the determination unit 10b determines that the semi-active damper D is in a contracting operation and outputs a signal indicating that the contracting operation is being performed to the control unit C. In addition, the detection part 10 may be comprised with a pressure switch instead of the structure of the pressure sensor 10a and the judgment part 10b. Since the pressure switch outputs an ON signal when the pressure in the piston side chamber 5 exceeds a predetermined pressure, the ON signal indicates that the semi-active damper D is being contracted when the predetermined pressure is set to the above-described threshold value. It becomes. On the other hand, when the pressure switch does not emit an ON signal, it can be seen that the semi-active damper D is in the extension operation.

Further, an acceleration sensor 20 is attached to the cylinder 1, and the acceleration sensor 20 detects an axial acceleration a acting on the cylinder 1 and inputs it to the control unit C. Therefore, as shown in FIG. 2, when the cylinder 1 is connected to the vehicle body B to be controlled, the rod 2 is connected to the carriage T, and the semi-active damper D is attached to the railway vehicle, the acceleration sensor 20 An acceleration substantially equal to the horizontal and horizontal acceleration of B can be detected.

Subsequently, as shown in FIGS. 1 and 3, the control unit C includes a bandpass filter 41 that removes steady acceleration, drift components, and noise during curve running included in the acceleration a detected by the acceleration sensor 20, and a band And a control processing unit 42 that outputs a control command to the variable damping valve 9 based on the acceleration a filtered by the pass filter 41 and the expansion / contraction direction of the semi-active damper D detected by the detection unit 10. Controls the damping force output by D. In addition, since the steady-state acceleration at the time of the curve driving | running | working included in the acceleration a by the band pass filter 41 is removed, only the vibration which deteriorates riding comfort can be suppressed.

As shown in FIG. 3, the control processing unit 42 calculates a damping force to obtain a damping force F that the semi-active damper D should generate based on the acceleration a detected by the acceleration sensor 20 and the expansion / contraction direction detected by the detecting unit 10. A unit 421, a current value calculation unit 422 for obtaining a current value I to be applied to the variable damping valve 9 based on the damping force F, and an input of the current value I to supply current to the variable damping valve 9 according to the current value I. A valve driving unit 423 is provided.

In this example, the damping force calculation unit 421 causes the semi-active damper D to function as a skyhook damper based on the Karnop control law, and attenuates based on the acceleration a and the expansion / contraction direction detected by the detection unit 10. Find the force F. In the Karnopp control law, if the skyhook damping coefficient is Cs and the speed of the vehicle body B to be controlled is V, the damping force F is F if the direction of the speed V and the expansion / contraction direction of the semi-active damper D match. = Cs × V, and if both do not match, the damping force F is set to 0. In other words, in the Karnop control law, the semi-active damper D exerts a damping force to suppress the vibration of the vibration suppression target, suppresses the vibration by suppressing the vibration and the vibration of the vibration suppression target cannot be suppressed. Make the force as small as possible so that the object to be controlled is not vibrated. The speed V of the vehicle body B can be obtained by differentiating the acceleration a detected by the acceleration sensor 20, and the extension / contraction direction of the semi-active damper D is detected by the detection unit 10, so that the damping force calculation unit 421 can grasp both.

When the speed V of the vehicle body B is positive in the left direction in FIG. 2 and the contraction side is positive in the expansion / contraction direction of the semi-active damper D, the damping force calculation unit 421 calculates the damping force F as follows. When the sign of the velocity V is positive and the signal from the detection unit 10 indicates contraction, or when the sign of the velocity V is negative and the signal from the detection unit 10 indicates expansion, the damping force calculation unit 421 The damping force F is obtained by calculating F = Cs × V. When the sign of the velocity V is positive and the signal from the detection unit 10 indicates expansion, or when the sign of the velocity V is negative and the signal from the detection unit 10 indicates contraction, the damping force calculation unit 421 The damping force F is set to zero.

Thus, since the semi-active damper D includes the detection unit 10, it can detect the expansion / contraction direction and can function as a skyhook damper based on the Karnop control law. The acceleration sensor 20 may be directly attached to the vehicle body B. However, if the acceleration sensor 20 is attached to the semi-active damper D, wiring work is not required when the semi-active damper D is installed on the railway vehicle. Further, the semi-active damper D does not include the acceleration sensor 20 and may receive an input of the acceleration to be controlled from the outside, or may receive an input of a target damping force to be output instead of the acceleration. . When receiving the input of the target damping force, if the direction in which the target damping force is generated is different from the expansion / contraction direction detected by the detection unit 10, the semi-active damper D is in the same direction as the direction in which the target damping force is generated. A damping force can be generated. Therefore, even when the input of the target damping force is received, it may be determined whether the damping force F is set to the target damping force or 0 according to the expansion / contraction direction detected by the detection unit 10.

Subsequently, the current value calculation unit 422 obtains the current value I to be supplied to the variable damping valve 9 based on the damping force F obtained as described above. Here, the variable damping valve 9 has a characteristic of having a pressure override in which the valve opening pressure changes in proportion to the amount of current supplied, but the pressure loss increases in accordance with the passing flow rate. The current value calculation unit 422 obtains the current value I in consideration of pressure override. Since the valve opening pressure of the variable damping valve 9 is minimized when the amount of supplied current is maximized, the current value calculation unit 422 determines that the damping force of the semi-active damper D is minimized when the damping force F is 0. Thus, the current value I is set to the maximum value.

In this example, the valve drive unit 423 is a driver that drives a solenoid (not shown) of the variable damping valve 9, and receives a current value I and supplies the variable damping valve 9 with a current amount equal to the current value I. Supply.

Although not shown, the control unit C specifically includes, for example, an acceleration sensor 20, an A / D converter for capturing a signal output from the detection unit 10, and a bandpass filter 41. A storage device such as a ROM (Read Only Memory) that stores a program used for processing necessary to control the damping force of the semi-active damper D based on the filtered acceleration a and the signal output from the detection unit 10; An arithmetic device such as a CPU (Central Processing Unit) that executes processing based on the program, and a storage device such as a RAM (Random Access Memory) that provides a storage area for the CPU may be included. Each part in the control processing part 42 of the control part C is realizable by execution of the said program of CPU. The bandpass filter 41 may be realized by executing a program of the CPU.

As described above, the semi-active damper D includes the cylinder 1, the rod 2 that is slidably inserted into the cylinder 1, and the rod-side chamber 4 and the piston-side chamber 5 that are slidably inserted into the cylinder 1 and inside the cylinder 1. And a piston 6, a tank 6, a suction passage 7, a damping passage 8, a variable damping valve 9, and a detection unit 10. The semi-active damper D configured as described above can determine whether the semi-active damper D is currently operating for expansion or contraction, and can adjust the damping force. Therefore, the semi-active damper D exhibits a damping force in a situation where the damping force in a direction capable of suppressing the vibration of the vehicle body B that is a vibration suppression target is exhibited, and in a situation where the vehicle body B is vibrated when the damping force is exhibited. The damping force can be reduced. Therefore, the semi-active damper D of the present invention can function as a skyhook damper without requiring the first on-off valve and the second on-off valve provided in the conventional semi-active damper. As described above, according to the semi-active damper D of the present invention, since the first on-off valve and the second on-off valve need not be provided, the entire apparatus can be downsized and the manufacturing cost can be reduced. In addition, according to the semi-active damper D of the present invention, since it is not necessary to provide the first on-off valve and the second on-off valve that cause a response delay in opening and closing, the vehicle body B and the carriage under a situation where a large damping force is exhibited. Even if T vibrates at a high frequency, the vehicle body B and the carriage T are not vibrated and the chatter vibration is not excited. Therefore, according to the semi-active damper D of the present invention, not only can the size and cost be reduced, but also the riding comfort in the vehicle can be improved.

In addition, the semi-active damper D of the present example includes a rectifying passage 13 that allows only the flow of hydraulic oil from the piston side chamber 5 toward the rod side chamber 4 so that the damping passage 8 communicates the rod side chamber 4 with the tank 6. It has become. The semi-active damper D configured in this way is set to a uniflow type in which hydraulic oil recirculates through the piston side chamber 5, the rod side chamber 4, and the tank 6 in order in one-way direction. It passes through the valve 9 and is discharged to the tank 6. Therefore, the semi-active damper D configured in this way can change the damping force with only one variable damping valve 9, and can more effectively reduce the size and cost of the apparatus. When the semi-active damper D is set to the biflow type, as shown in FIG. 4, the rectifying passage 13 is abolished from the structure of FIG. 1, and the damping passage 30 communicating the piston side chamber 5 and the rod side chamber 4, A variable damping valve 31 that is provided in the damping passage 30 to allow bidirectional flow and a base valve 32 that provides resistance to the flow of hydraulic oil from the piston side chamber 5 toward the tank 6 may be provided. Further, when the semi-active damper D is set to the biflow type, as shown in FIG. 5, a variable damping valve 33 is provided instead of the base valve 32 from the structure of FIG. 4, and hydraulic oil from the piston side chamber 5 to the rod side chamber 4 is provided. There may be provided a check valve 34 that allows only this flow. In this case, the variable damping

valves

31 and 33 are preferably one-way damping valves.

Further, the semi-active damper D of the present example includes an acceleration sensor 20 attached to the cylinder 1, and the cylinder 1 is connected to a vehicle body B as a vibration suppression target. If the semi-active damper D is configured in this way, an acceleration substantially equal to the acceleration of the vehicle body B can be detected, and wiring work with an external acceleration sensor, a control device, or the like becomes unnecessary, and the semi-active damper D is installed in the railway vehicle. The vibration control based on the Karnop control law can be realized with just this. If not only the acceleration sensor 20 but also the control unit C is integrated into the cylinder 1, the wiring work is completed only by connecting the power source and the control unit C, so that the mounting work on the railway vehicle is further simplified. .

Furthermore, in the semi-active damper D of this example, when the damping force cannot be exerted in the direction in which the vibration of the vehicle body B as the vibration suppression target is suppressed from the expansion / contraction direction detected by the detection unit 10, the damping force is minimized. It can function as a skyhook damper based on the control law, and a high damping effect can be obtained.

If the damping force cannot be exerted in the direction of suppressing the vibration of the vehicle body B as the vibration suppression target from the expansion / contraction direction detected by the detection unit 10, the damping force is not minimized, and a soft damping force greater than the minimum or minimum You may make it exhibit the medium damping | damping force of the magnitude | size about the largest middle. In this case, the damping force calculation unit 421 indicates that the sign of the velocity V is positive and the signal from the detection unit 10 indicates expansion, or the sign of the velocity V is negative and the signal from the detection unit 10 indicates contraction. If so, the damping force F may be a soft or medium damping force. What value should be set for the soft and medium damping force may be determined according to the railway vehicle. In this way, when the damping force is soft or medium, the vibration of the vehicle body B is slightly increased, but the vibration of the carriage T can be suppressed, and the vibration state of the railway vehicle is stable, so that the riding comfort is not impaired. Vibration control of the cart T is also possible.

The variable damping valve 9 is configured as shown in FIG. 6, for example, as shown in FIG. 6, a damping force adjusting passage TP, a fail passage FP, a relief valve portion RV, and an opening / closing valve provided in parallel in the middle of the damping passage 8. It may be composed of a part OV and a solenoid Sol.

The relief valve portion RV is provided in the damping force adjustment passage TP, and the on-off valve portion OV is provided in the fail passage FP. The on-off valve portion OV is energized so as to be opened by a spring, and is an electromagnetic on-off valve that closes when thrust is received from the solenoid Sol. Further, the on-off valve portion OV is normally energized by a spring when the solenoid Sol is not energized, communicates with the fail passage FP, and shuts off the fail passage FP when a predetermined amount of current is supplied to the solenoid Sol. It is said that.

The relief valve portion RV is driven by a thrust from the solenoid Sol via the on-off valve portion OV, and is energized by a spring when the solenoid Sol is not energized to maximize the valve opening pressure. ing. Further, when the solenoid Sol is energized and the on-off valve portion OV is set to the shut-off position, the thrust of the solenoid Sol acts on the relief valve portion RV as a force against the spring via the on-off valve portion OV. It has become. Therefore, when the solenoid Sol is energized, it is possible to adjust the valve opening pressure of the relief valve portion RV according to the energization amount. When the energization amount is increased, the valve opening pressure of the relief valve portion RV is decreased, and conversely, the solenoid Sol is not energized. In the state, the valve opening pressure of the relief valve portion RV becomes maximum. As described above, in the variable damping valve 9 of this example, the valve opening pressure of the relief valve portion RV can be adjusted and the opening / closing valve portion OV can be opened and closed with a single solenoid Sol.

In this example, a fail valve portion FV is provided in the fail passage FP. The fail valve portion FV is opened when the pressure on the upstream side becomes a predetermined pressure in a state where the fail passage FP is communicated by the on-off valve portion OV, and the valve opening pressure is reduced by the relief valve portion RV. A value smaller than the maximum valve opening pressure is set.

Therefore, this variable damping valve 9 can adjust the valve opening pressure of the relief valve portion RV by shutting off the on-off valve portion OV when the solenoid Sol is energized in a normal state where it can function normally. Damping force can be controlled.

Further, at the time of failure when the solenoid Sol cannot be energized (non-normal time), the on-off valve portion OV is opened, the fail passage FP is communicated, the fail valve portion FV is made effective, and the fail valve portion FV Demonstrates the damping force when the semi-active damper D expands and contracts. Therefore, the semi-active damper D functions as a passive damper during a failure.

The preferred embodiments of the present invention have been described in detail above, but modifications, changes, and changes can be made without departing from the scope of the claims.

This application claims priority based on Japanese Patent Application No. 2016-167521 filed with the Japan Patent Office on August 30, 2016, the entire contents of which are incorporated herein by reference.

Claims

A semi-active damper,
A cylinder,
A rod movably inserted into the cylinder;
A piston that is slidably inserted into the cylinder and divides the cylinder into a rod side chamber and a piston side chamber;
A tank,
A suction passage that allows only the flow of the working fluid from the tank toward the piston-side chamber;
A damping passage communicating the rod side chamber and the tank or communicating the rod side chamber and the piston side chamber;
A variable damping valve provided in the damping passage;
A detection unit that detects the expansion and contraction direction by the pressure in the piston side chamber,
Semi-active damper that suppresses the vibration of the vibration control target.
The semi-active damper according to claim 1,
A rectifying passage allowing only the flow of working fluid from the piston side chamber toward the rod side chamber;
The damping passage is a semi-active damper that communicates the rod side chamber and the tank.
The semi-active damper according to claim 1,
An acceleration sensor attached to the cylinder;
A semi-active damper in which the cylinder is coupled to the vibration suppression target.
The semi-active damper according to claim 1,
A semi-active damper that minimizes the damping force when the damping force cannot be exerted in the direction of suppressing the vibration of the vibration suppression target from the expansion / contraction direction detected by the detection unit.
The semi-active damper according to claim 1,
If the damping force cannot be exerted in the direction to suppress the vibration of the vibration suppression target from the expansion / contraction direction detected by the detection unit, the damping force is softer than the minimum, or the medium between the minimum and maximum And Semi-active damper.